Koito Manufacturing Company, Ltd.

Tomokazu Suzuki

Tomoyuki Ichikawa

Masayasu Ito

Hitoshi Takeda

Hiroki Shibata

Takanori Namba

Shoichiro Yokoi

Toshiyuki Tsuchiya

Tatsuhiko Yamamichi

Masato Watanabe

Kazushi Yoshikawa

A vehicular headlamp has a light source portion that provides a low beam lighting mode, a high beam lighting mode, and a dimming lighting mode, a light source power supply portion that supplies to the light source portion a lighting current having a current value according to lighting mode, a light distribution mechanism portion that switches light distribution of illumination light by the light source portion according to the lighting mode, and a control portion that, at least in the dimming lighting mode, causes the light source power supply portion to supply lighting current having a second current value lower than a first current value for the low beam lighting mode.

Vehicular headlamp

A vehicular lamp includes a light source, a cooling fan configured to cool the light source, a light source power supply module configured to drive the light source for emission of light, and a control module configured to execute an abnormal rotation detection of the cooling fan and to control the light source power supply module so that the quantity of light emitted from the light source is reduced in response to a detection of abnormal rotation.

Vehicular lamp

An object of the present disclosure is to reduce a failure rate due to a prolonged life span of a cooling fan while maintaining a satisfactory heat dissipating performance. When a signal indicating a first light-up state is input, a control unit sets a current value of an output current to a predetermined value such that a cooling fan is rotated at a predetermined rotation speed, and when a signal indicating a second light-up state is input, the control unit lowers the current value of the output current to a value lower than the predetermined value such that the rotation speed of the cooling fan is lower than the predetermined rotation speed. Therefore, the life span of the cooling fan may be prolonged while maintaining the satisfactory heat dissipating performance.

A vehicle lamp includes a light source (LED), a solenoid-type actuator, and a lamp control device LC. The light sourcelights up when a current flows therethrough. The actuatorcontrols a light distribution of light that is illuminated from the light source. The lamp control device LC controls lighting-up of the light sourceand driving of the actuator. The lamp control device LC includes a current control deviceand an actuator control device. The current control deviceoutputs a constant current. The actuator control deviceconnects the actuatorto the light sourcein series based on a predetermined signal so that the constant current, which is output from the current control device, flows through the light sourceand the actuator

Vehicle lamp

A discharge lamp lighting circuit is capable of preventing the discharge lamp from going out unexpectedly. The discharge lamp lighting circuit includes a DC-AC inverter which receives a power source voltage, boosts and converts the power source voltage into AC and supplies AC electric power to the discharge lamp. A control circuit sends a long cycle signal when the discharge lampis started. The cycle of the long cycle signal is longer than a frequency at the time of steady lighting. The control circuit sends a steady drive signal, which is a frequency at the time of steady lighting, to the DC-AC inverter. A cycle of the long cycle signal is set according to at least one of the power source voltage, the temperature of the discharge lamp lighting circuit or the extinguishing time.

Discharge lamp lighting circuit

A lighting circuit includes a DC/DC converting circuit for boosting an input DC voltage so as to produce boosted DC power, a detecting circuit for producing a detection signal in response to the output voltage of the DC/DC converting circuit, a DC/AC converting circuit for producing AC power to be supplied to the discharge tube from the boosted DC power, a starting circuit for starting up the discharge tube, and a control circuit for receiving the detection signal from the detecting circuit. The control circuit contains a capacitor which is charged based upon the detection signal, a first discharging unit for discharging the capacitor, a second discharging unit for providing a discharging path for the capacitor in response to turning-OFF of the input DC voltage, and a signal producing unit for producing a control signal used to adjust the output of the DC/DC converting circuit in response to a terminal voltage of the capacitor.

Lighting circuit

In a lighting apparatus for an illumination light source (discharge lamp or the like), a fly-back type DC-DC converter circuit comprises a transformer and a switching element. A control circuit is provided for controlling power supplied to the illumination light source, such that operation is controlled in a current boundary mode by a control signal sent from the control circuit to the switching element. A fluctuation generator circuit is provided for giving fluctuations to a frequency at which the switching element is driven by changing the power supplied to the illumination light source with reference to a target power value associated with the power control for the illumination light source.

Lighting apparatus for illumination light source

A power supply unit having a series regulator that changes an input DC voltage input from a DC power supply into a stabilized output DC voltage lower than the input DC voltage, includes: a power consuming unit, provided on a direct current path between the DC power supply and the series regulator, including a parallel circuit formed by a first fixed resistor and a semiconductor device; and a current setting unit operable to set the amount of a current flowing between a current input and a current output of the semiconductor device, wherein the current input of the semiconductor device is arranged on the DC power supply side thereof, the current output of the semiconductor device is arranged on the series regulator side thereof, and a setting input of the semiconductor device is connected to a setting output of the current setting unit.

Growing community of inventors

Shizuoka, Japan

Tomokazu Suzuki